DE-OS No. 02 746 describes a supporting matrix comprising smooth and corrugated, spirally wound metal foils of high temperature resistant steel. This reference also teaches placing the supporting matrix wound under prestressing in a jacket in order to immobilize it in the axial direction. However, this fastening method has been found inadequate in view of the mechanical stresses (strong vibrations) to which the assembly is subjected.
In DE-OS No. 27 20 322, the use of electron beam welding is proposed for fastening the supporting matrix and the jacket. The weld head, which extends helically around the circumference of the jacket, may under certain conditions weaken the mechanical strength of the jacket and cause the supporting matrix to be cut in the direction of the electron beam. Furthermore, such a design does not permit the supporting matrix to be thermally insulated with respect to the external environment.